There are many types of bearings that are used in various applications. Such bearings include journal bearings, roller bearings, spherical bearings and hourglass type bearings. In general, these bearings have an inner race that is disposed at least partially in an outer race. The inner race and outer race are movable relative to one another. There is an annular cavity between the inner race and the outer race that typically contains a lubricant. One well known problem with bearings is the ingress of debris and contaminants into the annular cavity which can cause premature failure of the bearings due to degradation of the lubrication. Moreover, operation of the bearing can cause the lubricant to inadvertently escape from the annular cavity.
In an effort to mitigate the aforementioned problems, seals have been positioned across the annular cavity to maintain the lubricant in the cavity and to prevent the ingress of debris into the annular cavity. However, during operation, such seals become dislodged from the bearing and fail to function. In addition, such seals have often been too flexible, thereby allowing the seal to glide over debris and sweep the debris into the annular cavity.
Bearings are typically used in aircraft wing flap arrangements. For example, U.S. Pat. No. 8,714,493 describes a trailing edge flap arrangement for an aircraft wing that includes a drop linkage arrangement that includes one or more bearings. The subject matter of U.S. Pat. No. 8,714,493 is incorporated by reference herein, in its entirety. U.S. Pat. No. 8,714,493 is assigned to Airbus® Operations Limited, Bristol United Kingdom.
One of Airbus's® aircraft that employees the drop linkage arrangement is known as the Airbus® and A-350® aircraft. Airbus® and A-350® are a registered trademarks of Airbus Corporation, having numerous registered trademarks therefor. The Airbus® A-350® aircraft is defined by a wing planform—with a 64.7-meter wingspan, a total area of 442 square meters, and high swept leading edge. The Airbus® and A-350® aircraft includes a drop-hinge linkage mechanism to improve wing flap deployment kinetics, along with the introduction of a downwards movement for the upper wing spoilers to fill the gaps that occur when flaps are extended. In addition, the Airbus® and A-350® aircraft includes flight computer performs in-flight trimming of the inboard and outboard flaps, creating a variable camber wing that adapts to different flight conditions. In one embodiment, the Airbus® and A-350® aircraft employs 53 per cent of composites (i.e., Carbon Fiber Reinforced Plastic) in the fuselage and wing to reduce the need for fatigue-related inspections required on more traditional aluminum jetliners. The Airbus® and A-350® aircraft has a seating capacity between 280-440. The Airbus® and A-350® aircraft has two engines (e.g., two Rolls-Royce Trent XWB engines). The Airbus® and A-350® aircraft has a flying range of up to 7,950 nautical miles.